Photographic inhibitor-releasing developers



United States Patent 3,379,529 PHOTOGRAPH-HG INHIBITOR-RELEASINGDEVELOPERS Ralph Frederick Porter, Judith A. Schwan, and John W. Gates,Jr., Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Feb. 28, 1963, Ser.No. 261,835

19 Claims. (CI. 96-36) This invention concerns inhibitor-releasingdevelopers and more particularly photographic emulsions containing suchdevelopers.

It is well-known in the photographic art to employ developing agents inthe photographic emulsion. These developing agents can be activated toprovide development of the latent image and in some instances to hardenor tan the colloid containing the silver halide in the ex posed regionswhich will subsequently form relief images after the unhardened imageshave been removed. However, the presence of the developing agent in thephotographic emulsion may have an adverse effect on the keepingqualities of the emulsion resulting in an overall hardening of theemulsion or fogging. In addition, the developing action carried on bythe use of an alkaline agent which initiates development may result infog or other adverse results. Therefore, it has been desirable toincorporate a development inhibitor agent along with the developer whichwould reduce fog and improve the keeping characteristics of thephotographic emulsion. Preferably, such an inhibitor would also resultin inactivating the developer or keeping it in an inactive state untilsuch time that it is needed for carrying out development followingexposure.

Hydroquinone has been combined with various materials in the prior artfor use as developers or for in corporating in photographic emulsions.For instance, certain compounds of this type have been used wherein itis desired to eliminate and minimize the need for washing or stabilizingoperations in liquid photographic baths subsequent to the formation ofthe silver image, for instance in the diffusion transfer systems,particularly where prints are desired from a silver halide emulsionwhich has been substantially underexposed in relation to its ASAexposure index. However, these prior art hydroquinone derivatives do notprovide inhibitors at the site of development or produce the desiredeffect of reducing contrast with no loss of speed.

We have found a substituted hydroquinone which, upon activation,produces free hydroquinone and also releases an inhibitor at or near thesite of development, resulting in reduced contrast and increased edgeeffects with little or no loss in speed.

One object of this invention is to provide inhibitorreleasingdevelopers. Another object is to provide photographic emulsionscontaining inhibitor-releasing developers. A further object is toprovide developer containing emulsions having reduced contrast andincreased edge effects with little or no loss in effective speed. Afurther object is to provide a development inhibitor in chemicalcombination with a developing agent which releases the inhibitor at ornear the site of development. A still further object is to provide arylor alkyl mercaptotetrazole substituted hydroquinones. Other objects willbe apparent from the following disclosure.

"Ice

The hydroquinone developers which are useful in our invention arepreferably prepared by reacting a p-benzoquinone with amercaptotetrazole.

The phenylmercaptotetrazole derivatives of hydroquinone are preferablyincorporated in the photographic emulsion by forming a dispersion in ahigh boiling crystalloidal solvent of the type described in Jelley etal., U.S. Patent 2,322,027. These developers may be substituted in anamount of 5 to mol percent depending upon the particular compound andthe desired decrease in contrast.

The following reaction is typical of the general method of preparingthese inhibitor-releasing developers (IRD):

0 OH H l N-N The most useful compounds within the scope of our inventionhave the following general formula:

wherein X, Y and Z represent a hydrogen atom, alkyl groups (for examplealkyl groups having about 1-20 carbon atoms, such as methyl, butyl,octyl, decyl, tridecyl, eicosyl, etc.), OH, amine, aryl groups (forexample aryl groups such as phenyl, tolyl, xylyl, etc.), halogen,heterocyclic groups (for example heterocyclic groups such as tetrazolyl,thiazolyl, quinolinyl, etc.), or mercaptophenyltetrazole and Rrepresents an aryl group (such as phenyl, tolyl, xylyl, etc.) or a loweralkyl group, (for example methyl, ethyl, propyl, butyl, amyl, etc.). Xand Y are members of a carbocyclic ring.

The substituents on the hydroquinone ring are not critical and may bethe same or different. Preferably, the substituted hydroquinone will bean active developer, However, the activity of the substitutedhydroquinone will depend upon its desired use and may be negligible.

The IRD hydroquinone developers useful in this invention may be preparedas shown by the following preparation ofl-phenyl-5-tetrazolylthio)p-benzoquinone.

In approximately 20 g. portions p-benzoquinone (86.5 g.) was added to achilled suspension of l-phenyl-S-mercaptotetrazole (143 g.) in 500 ml.of methanol. The temperature was maintained below 20 during addition andafter addition was complete the mixture was allowed to stand for 2%hours. Collection of the solid materials gave 218 g. of white solid(l-phenyl-S-tetrazolylthio) hydr'oquinone M.P. 211-212. The productcould be recrystallized from large volumes of acetone to yield whiteprisms, M.P. 212-2l6.

Hydroqulnone and Structure Compound Empirical Molecular Melting PointNumber Formula Weight 2,S-bis-(Qehloroacetoxy)-3-(1pllenyl-5-tetrazoly1thio) 13 C1TH1205C11N4S 471. 28 128-131" (1.

liydi'oquinonc.

0 2C CHzCl 0101120 01 I s i O H N N 2,5-dimethyb3(l-phenyl-Ew-tetrazoiyltliio)liydroquin0ne 14 C HHOZN4S 314. 36 213-4 d.

N-N I CII3- S -C i I N-N 0 II I2,6-dinietliyl3-(1phenylfi-tetrazolylthio)liydroquinone 15 C H 0 N;S314. 36 188.

C H; CII;

NN ll S-C I l l 0 II 12,3-(1iniethy1-5-(1-phenyl-S-tetrazolyltliio)hydroquinone 16 G H 401N S314. 36 155-7" (1.

NN H CH; -SC l N NZ-n-pentadecyl-x-O-phenyl--t-etrazoly1thio)liydroquiuone. 17 C H4UON4S49G. 63 1588 d.

Cz II4oOzN4S 496. 63 85 (1. 11

N-N 31 u NN I O H The following examples are intended to illustrate oursq. ft. is exposed, and developed in a developer containing 0.67 g./1.(67 mol percent) of hydroquinone and 0.87

invention but not to limit it in any way.

g./ 1. (33 mol percent) of (l-phenybS-tetrazolylthi0) EXAMPLE 1hydroquinone, 0.25 g./1. of. Elon, 40 g./l. of sodium A coating of asilver bromoiodide photographic emulsulfite, 25 g./l. of sodiumcarbonate monohydrntc, and sion having 500 mg. of gel and 300 mg. ofsilver per 1 g./l. of potassium bromide adjusted to pH 11.5 with sodiumhydroxide, for six minutes at 68 and then fixed and washed as usual.Relative to a similar developer but containing 1 g./l. of hydroquinoneand no thiohydroquinone derivative, this gave a 4 percent reduction incon trast and .07 log E loss in toe speed. X-ray line exposures showedmore density at an edge than in an extended exposed area.

EXAMPLE 2 In a test similar to the above and using a variety ofcompounds, the following results were obtained:

Strips of a silver bromoiodide photographic emulsion coating wereexposed on an intensity scale sensitometer and processed according tothe procedure given in Example 1, except that only 10 mol percent of thehydroquinone in the check developer was replaced with each of thehydroquinones described as follows.

A OH H3 so NN CH3 B OH O I CH5 S-C\\ Developer A Hydroquinone 1 Elon .25Sodium sulfite 40* Sodium carbonate monohydrate 25 Potassium bromide 1Water to 1 liter, pH 11.5.

Developer B As in Developer A, except:

G./l. Hydroquinone .90 (A) .29

Developer C As in Developer A, except:

G./l. Hydroquinone .90 (B) .265

The following results were obtained.

Percent of Compound Concentration Spd. vs. Ck. Reduction (A) mol percent.05 15 (B) 10 mol percent .10 3

It can be seen from the above comparison that the phenyl mercaptotetrazole hydroqinone (A) derivative gives considerable reduction incontrast with no significant loss in speed. The benzoxazolylthiolhydroquinone derivative (B) is much less effective in reducing thecontrast of the developed image.

When hydroquinone-phenyl mercapto tetrazole derivatives are compared toother heterocyclic mercaptanhydroquinones such as hydroquinonederivatives of mercapto benzothiazole, mercapto benzimidazole, mercaptothiazoline, mercapto pyridine and etc., similar advantages are obtainedwith the hydroquinone-phenyl mercapto tetrazole derivative as describedin the comparative example given.

10 EXAMPLE 3 In a test similar to the above and using a variety ofcompounds, the following results were obtained:

Concentration Speed vs, Ck Percent -y Compound Q) Reduction 2 10 molpercent. 1 33 mol percent. 14 10 mol percent. 3 5 mol percent 5 100 molpercent 34 Equal In all cases a lower minim-um density relative to acheck developer and increased edge effects were noted.

EXAMPLE 4 A sample of silver bromoiodide film was exposed to X-ray usinga knife edge to get a sharp edge. When developed in a formula containing1 g./l. of hydroquinone, 5.2 g./l. of (1-phenyl-5-tetrazolylthio)hydroquinone, g./l. of sodium sulfite, 30 g./l. of sodium carbonatemonohydrate, and 0.1 g./l. of potassium bromide at a pH of 11.5, fog wasrepressed adjacent to the exposed area. This type of effect in anegative is useful in producing enhanced sharpness in a positive print.

EXAMPLE 6 Coatings 48810-A silver chlorobrornide photographic emulsionwas coated on a cellulose acetate support at 300 mg. Ag/ft. and 692 mg.gel/ft.

488l4-The same as coating 48810 except just before coating, a dispersionof X-methyl-(l-phenyl-S-tetrazolylthio)hydroquinone inN-n-butylacetanilide was added, to yield .025 mole of the hydroquinoneper mole of silver halide.

Each of the above coatings was exposed for /s" on an Eastman IBSensitometer, developed 5 at 68 F. in Kodak Developer DK50, rinsed,fixed in Kodak F-S, washed and dried. Another set of film strips wasexposed and processed as above except that development was for 4 inKodak Developer D-19. Sensitometric results are given below. Speed ismeasured at a density of 0.30 over fog.

Coating Relative Speed Relative Speed Addition of the IRD hydroquinonedeveloper from a coupler solvent dispersion produced contrast reductionwith no loss in toe speed.

EXAMPLE 7 Coatings 2 (4-methyl-phenyl x(1-phenyl-5'tetrazolylthio)hydroquinone was added.

94-8--The same as coating 94-5 except 0.1 mole of 2 n-pentadecylx-(1-phenyl-5-tetrazolylthio)hydroquinone was added.

117-1The same as coating 94-5 except 0.1 mole of 2,5dimethyl-3-(l-phenyl-5-tetrazolylthio)hydroquinone was added.

Each of the above coatings was exposed on an Edgeton Germeshausen andGrier Mark V1 sensitometer and processed as in Example 1.

5DK-50 4D19 Coating Relative 7 Fog Relative 'y Fog Speed Speed EXAMPLE 8Coatings 5' DK-50 4 D-10 Coating Relative 'y Fog Relative 'y Fog SpeedSpeed The beneficial eifects obtained by the 1RD hydroquinone developercannot be obtained by adding the development-inhibitor itself, such asphenylmercaptotetrazole, directly to the emulsion. When thedevelopmentinhibitor is added directly to the emulsion, speed losseswith no contrast reduction occur even at much lower levels than thoseused for the 1RD thiohydroquinones. With compounds of this type thedevelopment-inhibitor appears to be released imagewise, thereby givingthe contrast reduction with no speed loss.

EXAMPLE 9 Coatings 1265-A silver chlorobrornide emulsion was coated on acellulose acetate support. (Control) 126-1-Similar to the above exceptjust before coating, a dispersion of 2,5-dimethyl-3-(l-phenyLS-tetrazolylthio) hydroquinone in N-n-butylacetanilide was addedat a concentration of 0.1 mole of the hydroquinone/mole of silverhalide.

1263Similar to the above except just before coating, a dispersion of3-(2-benzoxazolylthio)-2,5-dimethylhydroquinone in N-n-butylacetanilidewas added at a concentration of 0.1 mole of the hydroquinone/molc ofsilver halide.

12 Each of the above coatings was exposed on an intensity scalesensitometer, developed for five minutes in Kodak Developer D-19,rinsed, fixed in Kodak F-S, washed and dried with the following results:

Coating No. Rel. Speed 1 Fog 126-5 (Control)- 123 5. 10 05 126-1 120 3.26 03 126-3 4. 80 07 It can be seen from the above comparison that thepreferred PMT-hydroquinone derivative gives an appreciable reduction incontrast with no significant loss of speed whereas other heterocyclicmercaptan-hydroquinone derivatives yield no appreciable reduction incontrast and desensitizes.

EXAMPLE 10 In order to prepare a gelatin overcoat for a color negative,the following dispersion is prepared. A separate dis-- persion isprepared as a control without any hydroquinone derivative.

Part A 5,8-ethano-2-(l-phenyl 5 tetrazolylthio) 5,8dihydro-1,4-naphthohydroquinone g 136 Methyl alcohol ml 136 Di-n-butylphthalate "ml..- 272 1 Heat at 70 C. to dissolve them. Cool to 40 C.

Part B 2 10% gelatin solution g 1360 Distilled water rnl 1360Mucochloric acid (2.7% aqueous solution) ml 136 Heat to 40 C.

Part A is slowly added to Part B with the aid of mechanical agitation.The solution obtained is then passed through a Caton-Gaulin laboratorycolloid mill five times. The colloid mill is then rinsed and thedispersion is adjusted to a weight of 3775 g. chill set and stored in arefrigerator.

The above dispersions are then prepared as follows:

A negative element was made in which the top layer of a basic colornegative is prepared as follows:

Part I 1 Dispersion g 3775 Distilled water ml 2225 Heat to 40 C.

Part II 2 10% gelatin solution g 3180 Distilled water "ml-.. 12,000Mucochloric acid (2.7% aqueous solution) 2 Heat to 40 0., adjust pH to5.5.

Parts I and 11 are then combined and diluted with distilled water to22,700 ml. This solution is coated as the top layer of a basic colornegative to yield a coverage of approximately mg. of gelatin per squarefoot and 40 mg. of the hydroquinone per square foot. This coating iscompared to the control coating. After exposure on an intensity scalesensitometer the negatives are processed in an aqueous activatorcontaining 3.5 percent hydroxyethyl cellulose, 4.5 percent NaOH and 2.0percent benzotriazole, and the released dyes are transferred imagewiseto a receiving sheet by lamination in the known manner.

The following illustrates the basic color negative structure asdescribed in U.S. Patent 2,774,668.

The receiving sheet is a paper support carrying a gelatino coatingcontaining a mixture of poly-4-vinyl pyridine andl-phenyl-5-mercaptotetrazole.

The following results show the effectiveness of the thioetherhydroquinone as an auxiliary developer compared to the control.

The IRD developer compounds of our invention can be incorporated in anordinary photographic silver halide emulsion, or colloidal dispersion ofa water-permeable hydrophilic colloid suitable for preparing anundercoat or an overcoat for such silver halide emulsion, by mixing asolution or dispersion of the developer compound with the silver halideemulsion, or dispersion of hydrophilic colloid, prior to coating. Forexample, an IRD developer can be made up as an oil dispersion bystirring a solution of grams of the IRD developing agent into 40 gramsof warm tricresylphosphate, and then mixing thi solu tion with 100 gramsof a 10 percent aqueous gelatin solution containing 10 cos. of a 5percent aqueous solution of an alkylnaphthylene sodium sulfonate wettingagent. The resulting dispersion can then be homogenized by passing for 5times through a colloid mill to produce a homogeneous colloiddispersion. Solvents other than tricrcsylphosphate can be employed,including any of the crystalloidal compounds described in Jelley andVittum US. Patent 2,322,027, issued June 15, 1943. The resultingcolloidal dispersion can then be added to a photographic silver halideemulsion, or to a dispersion of a waterpermeable hydrophilic colloid,adapted for preparation of an undercoat or overcoat for such silverhalide emulsion.

Instead of adding the oil dispersion directly to the liquid silverhalide emulsion or colloidal dispersion, it can be dried for storagepurposes and then be reconstituted for use by merely mixing with water.

The IRD developing agents of our invention can be adapted for additionto a liquid silver halide emulsion or colloidal dispersion by othermeans as well. Suitable methods will depend largely upon the solubilitycharacteristics, particularly in water or polar solvents, of theparticular precursors in question.

After addition of the dispersion or solution of the IRD developing agentsubstance to the liquid emulsion or colloidal dispersion, the mixture isstirred to assure uniform results, or passed through a blending device,such as a colloid mill or Waring Blendor. A uniform coating can then bemade on a suitable support and the coating dried. Suitable supportscomprise any of the well known supporting materials, such as celluloseester film base (e.g., cellulose acetate, cellulose nitrate, celluloseacetate butyrate, cellulose acetate propionate, etc.), polyethylene,polypropylene, polystyrene, polyethylene terephthalate and otherpolyesters, paper, polycarbonates, etc.

The photographic elements of our invention comprising a photographic IRDdevelopment agent either in the photographic silver halide emulsionlayer, or layer contiguous thereto, or both, can then be exposed to anoriginal or negative and developed by merely treating the exposedemulsion layer with an alkaline activator bath. Typical activator bathscomprise, for example, an aqueous solution of an alkaline material, suchas sodium carbonate, sodium hydroxide, potassium carbonate, potassiumhydroxide, mixtures of sodium hydroxide and sodium sulfite, etc.Suitable baths can comprise, for example, an aqueous solution containingabout 1 percent sodium hydroxide and 5 percent sodium sulfite. A bath ofthe latter type is quite suitable for developing an exposed emulsionlayer in about 30 seconds when the activator bath is at about 68 F.Modifications can easily be made in the activator baths withoutdeparting from the spirit and scope of the invention. For example, anaqueous solution comprising about 4 percent of sodium carbonate and 5percent of sodium sulfite produces development in about 30 seconds at 68F. Another aqueous activator solution comprising 2 percent sodiumhydroxide and 5 percent sodium sulfite produces useful photographicimages in a few seconds when heated at F. Particnlarly useful activatorsolutions have a pH of at least about 9.0 and preferably of at leastabout 10.5.

The activator solutions of the present invention can be applied to anexposed photographic element in any number of known ways, such as bydipping, spraying, or other suitable surface applications. If desired, athickener can be added to the activator solution to increase theviscosity of the composition and make it more adaptable for continuousprocessing. Viscous compositions can then be removed by squeegeeing orwater spraying. The photographic element can then be stabilized byconventional fixation or stabilization, such as by sodium thiosulfate.

The concentration of the IRD developers used in our invention will vary,depending upon the particular chemical compound involved and thelocation of the compound within the photographic element. That is, ifthe IRD developer is incorporated within the silver halide emulsionundergoing development, it may be desirable to use a somewhat differentconcentration than would be used if the IRD developer were incorporatedin a layer contiguous to the photographic silver halide emulsion. Auseful concentration of IRD developer for incorporation in the emulsionis from about 0.01 to 4.0 moles per mole of silver halide. Aparticularly useful range is from about 0.1 to 2.0 moles per mole ofsilver halide. For incorporation in a layer contiguous to the silverhalide emulsion layer, somewhat larger concentrations of IRD developercan be tolerated without adverse effects. A particularly useful effectof our invention is that even when incorporated Within the silver halideemulsion, the IRD developers have little or no desensitizing effects. Inmany cases, this is not true where development-inhibitors or developingagents, per se, are incorporated within the silver halide emulsionlayers.

Photographic silver halide emulsions useful in our invention compriseany of the ordinarily employed silver halides developing-out emulsions,such as, silver-chloride, -chlorobromide, -chloroiodide,-chlorobromoiodide, -bromide and -bromoiodide emulsions. Any of theconventionally employed water-permeable hydrophilic colloids can beemployed in the silver halide emulsions, or in layer contiguous thereto.Typical water-permeable hydrophilie colloids include gelatin, albumin,polyvinyl alcohols, agar agar, sodium alginate, hydrolyzed celluloseesters, hydrophilic polyvinyl copolymers, etc.

Photographic silver halide emulsions useful in our invention can alsocontain such addenda as chemical sensitizers, e.g., sulfur sensitizers(e.g., allyl thiocarbamate, thiourea, allyl isothiocyanate, cystine,etc.), various gold compounds (e.g., potassium chloroaurate, aurictrichloride, etc.). (See U.S. Patents 2,540,085, 2,597,856 and2,597,915, etc.)

Photographic silver halide emulsions useful in our invention can also besensitized by other means, such as by alkylene oxide polymers, many ofwhich are well known to those skilled in the photographic art. Typicalpolyalkylene oxide polymers include those of U.S. Patents 2,423,549 and2,441,389.

The emulsions of the invention can also contain speedincreasingcompounds of the quaternary ammonium type as described in U.S. Patents2,271,623, issued Feb. 3, 1942; 2,288,226, issued June 30, 1942;2,334,864, issued Nov. 23, 1943; or the thiopolymers as described inGraham et al., U.S. application Ser. No. 779,839, filed Dec. 12, 1958,now Patent No. 3,046,129; and Dann et al., US. application Serial No.779,874, now Patent No. 3,046,134, filed Dec. 12, 1958.

The emulsions may also be chemically sensitized with reducing agentssuch as stannous salts (Carroll U.S. Patent 2,487,850), polyamines suchas diethylene triamine (Lowe and Jones U.S. Patent 2,518,698),polyamines such as spermine, (Lowe and Allen U.S. Patent 2,521,925), orbis-(B-aminoethyl) sulfide and its watersoluble salts (Lowe and JonesU.S. Patent 2,521,926).

The emulsions may also be stabilized with the mercury compounds ofAllen, Byers and Murray U.S. application Serial No. 319,611; Carroll andMurray U.S. application Serial No. 319,612; and Leubner and Murray U.S.application Serial No. 319,613, all filed Nov. 8, 1952, now U.S. Patents2,728,663, 2,728,664 and 2,728,665, respectively, granted Dec. 27, 1955.

The addenda which we have described may be used in various kinds ofphotographic emulsions. In addition to being useful in x-ray and othernonoptically sensitized emulsions, they may also be used inorthochromatic, panchromatic, and infrared sensitive emulsions. They maybe added to the emulsion before or after any sensitizing dyes which areused. The agents may be used in emulsions intended for colorphotography, for example, emulsions containing color-forming couplers oremulsions to be developed by solutions containing couplers or othercolor-generating materials, emulsions of the mixed-packet type, such asdescribed in Godowsky, U.S. Patent 2,698,- 794, issued J an. 9, 1955; oremulsions of the mixed-grain type, such as described in Carroll andHanson U.S. Patent 2,592,243.

It has been found that the development rate of the IRD developers abovecan be improved by adding an auxiliary developing agent either to thesilver halide emulsion layer, or a hydrophilic layer contiguous thereto.Typical auxiliary developing agents include those described in thecopending application Serial No. 134,014, now abandoned, filed August 5,1961, of P. H. Stewart, G. E. Fallesen and J. W. Reeves, Jr. Typicalauxiliary developing agents described in this application include3-pyrazolidone compounds containing an alkyl (e.g. methyl, ethyl, etc.)or aryl substituent (e.g. phenyl, p-tolyl, etc.). In addition, suchpyrazolidone developing agents can contain an acyl or acyloxysubstituent which can be hydrolyzed from the 3-pyrazolidone compound bytreatment with the above activator solutions to produce the desiredauxiliary developing compound. Typical auxiliary developing agentsinclude, for example, 1-phenyl-3-pyrazolidone, l-p-tolyl-3-pyrazolidone, 1-phenyl-5-methyl-3-pyrazolidone,l-acetamidoprenyl-3-pyrazolidone, 3-acetoxy-1-phenyl-3-pyrazolidone(Enol ester), Z-(pyridinium acetyl)-l-phenyl-3- pyrazolidone chloride,l-phenyl 4,4 dimethyl-3-pyrazolidone, l-phenyl 4 methyl-3-pyrazolidone,l-phenyl-Z- benzoyl-3-pyrazolidone, l-phenyl 2 lauroyl-3-pyrazolidone,1-phenyl-2-chloroacetyl-3-pyrazolidone, etc.

The concentration of auxiliary developing agents can be varied and, ofcourse, no auxiliary developing agent need be employed unless sodesired. Useful concentrations of auxiliary developing agents vary fromabout 0.01 mole to 2.0 moles based on the IRD developing agent compound.Depending upon the particular auxiliary developing agent employed,larger or smaller quantities can be used.

The IRD developers of our invention can be used in emulsions intendedfor use in diffusion transfer processes which utilize the undevelopedsilver halide in the nonimage areas of the negative to form a positiveby dissolving the undeveloped silver halide and precipitating it on areceiving layer in close proximity to the original silver halideemulsion layer. Such processes are described in Rott U.S. Patent2,352,014, issued June 20, 1944, and Land U.S. Patents 2,584,029, issuedJan. 29, 1952; 2,698,236, issued Dec. 28, 1954, and 2,543,181, issuedFeb. 27, 1951; and Yackel et al. U.S. Patent 3,020,155, issued Feb. 6,1962. They may also be used in color transfer processes which utilizethe diffusion transfer of an imagewise distribution of developer,coupler or dye, from a light-sensitive layer to a second layer, whilethe two layers are in close proximity to one another. Color processes ofthis type are described in Land U.S. Patents 2,559,643, issued July 10,1951, and 2,698,798, issued Ian. 4, 1955; Land and Rogers BelgianPatents 554,933 and 554,934, granted Aug. 12, 1957; InternationalPolaroid Belgian Patents 554,212, granted July 16, 1957, and 554,935,granted Aug. 12, 1957; Yutzy U.S. Patent 2,756,142, granted July 24,1956, and Whitmore and Mader U.S. patent application Ser. No. 734,141,now abandoned, filed May 9, 1958. They may also be used in emulsionsintended for use in a monobath process such as described in Haist et al.U.S. Patent 2,875,048, issued Feb. 24, 1959, and in web-type processes,such as the one described in Tregillus et a1. U.S. patent applicationSer. No. 835,473, filed Aug. 24, 1959, now abandoned.

Of course, the activator solutions which are used in our invention arestable for extended periods of time and are not subject to the harmfuldecomposition reactions so common to conventional photographicdeveloping solutions when these developing solutions are stored forextended periods of time. No special precautions are required to preventoxidation of the activator solutions since they are inherently quitestable. If desired, the activator solutions can be incorporated in acarrier, such as gelatin and coated in contact with the photographicsilver halide emulsion layer which contains the development precursorsof our invention. After exposure, the development can be effected merelyby heating the photographic emulsion layer to a temperature sufficientto release water, which may be present in the support or in a separatelayer in the photographic element. This water then dissolves theactivator solution from the hydrophilic colloid layers and takes it intothe photographic halide emulsion layer where development is effected.

The elevated temperatures from about 150 C. are usually sufficient toeffect development in this manner. If desired, additional moisture canbe added by spraying steam upon the sensitive surface of thephotographic element.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention as described hereinabove and as defined in the appendedclaims.

We claim:

1. A photographic element comprising a support and a photographic silverhalide emulsion layer, and integral with said photographic element awater-permeable hydrophilic colloid layer containing a compoundrepresented by the following general formula:

wherein X and Y represent a member selected from the class consisting ofa hydrogen atom, alkyl groups having about 1 to carbon atoms, OH, amine,an aryl group, a halogen atom, a heterocyclic group and members of acarbocyclic ring, Z represents a member selected from the classconsisting of a hydrogen atom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group, a halogen atom and a heterocyclic groupand R represents a member selected from the class consisting of an arylgroup and a lower alkyl group.

2. A photographic element comprising a support and a photographic silverhalide emulsion layer comprising a water-permeable hydrophilic colloidlayer containing a compound represented by the following generalformula:

wherein X and Y represent a member selected from the class consisting ofa hydrogen atom, alkyl groups, having about 1 to 20 carbon atoms, OH,amine, an aryl group, a halogen atom, a heterocyclic group and membersof a carbocyclic ring, Z represents a member selected from the classconsisting of a hydrogen atom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group, a halogen atom and a heterocyclic groupand R represents a member selected from the class consisting of an arylgroup and a lower alkyl group.

3. A photographic element comprising a paper support and a photographicsilver halide emulsion layer comprising a water-permeable hydrophiliccolloid layer containing a silver halide developer and a compoundrepresented by the following general formula:

wherein X and Y represent a member selected from the class consisting ofa hydrogen atom, alkyl groups having about 1 to 20 carbon atoms, OH,amine, an aryl group, a halogen atom, a heterocyclic group and membersof a carbocyclic ring, Z represents a member selected from the classconsisting of a hydrogen atom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group, a halogen atom and a heterocyclic groupand R represents a member selected from the class consisting of an arylgroup and a lower alkyl group.

4. A photographic element comprising a support and a photographic silverhalide emulsion layer comprising a water-permeable hydrophilic colloidlayer containing a colloidal dispersion of a compound in awater-insoluble,

Water-permeable crystalloidal solvent, said compound represented by thefollowing general formula:

wherein X and Y represent a member selected from the class consisting ofa hydrogen atom, alkyl groups having about 1 to 20 carbon atoms, OH,amine, an aryl group, a halogen atom, a heterocyclic group and membersof a carbocyclic n'ng, Z represents a member selected from the classconsisting of a hydrogen atom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group, a halogen atom and a heterocyclic groupand R represents a member selected from the class consisting of an arylgroup and a lower alkyl group.

5. A photographic element comprising a support and a photographic silverhalide emulsion layer comprising a water-permeable hydrophilic colloidlayer containing a colloidal dispersion of .a compound intricresylphosphate, said compound represented by the following generalformula:

NN X s-o N-N Y Z I I R on wherein X and Y represent a member selectedfrom the class consisting of a hydrogen atom, alkyl groups having about1 to 20 carbon atoms, OH, amine, an aryl group, a halogen atom, aheterocyclic group, and members of a carbocyclic ring, Z represents amember selected from the class consisting of a hydrogen atom, alkylgroups having about 1 to 20 carbon atoms, OH, amine, an aryl group, ahalogen atom and a heterocyclic group and R represents a member selectedfrom the class consisting of an aryl group and a lower alkyl group.

6. A photographic element comprising a support and a photographic silverhalide gelatino emulsion layer containing a compound represented by thefollowing general formula:

a member selected from the class consisting of an aryl group and a loweralkyl group.

7. A photographic element comprising a support and a photographicuntanned silver halide gelatino emulsion layer containing a compoundrepresented by the following general formula:

wherein X and Y represent a member selected from the class consisting ofa hydrogen atom, alkyl groups having about 1 to 20 carbon atoms, OH,amine, and aryl group, a halogen atom, a heterocyclic group and membersof a carbocyclic ring, Z represents a member selected from the classconsisting of a hydrogen atom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group and a halogen atom, a heterocyclic groupand R represents a member selected from the class consisting of an arylgroup and a lower alkyl group.

8. A photographic element as defined is claim 2 wherein said compound is2-methyl-5-(l'-phenyl-5'-tetrazolylthio)hydroquinone.

9. A photographic element as defined in claim 2 Wherein said compound is(l-phenyl-S-tetrazolylthio)hydroquinone.

10. A photographic element as defined in claim 2 wherein said compoundis 2-n-pentadecyl-X-(l-phenyl-S- tetr-azolythio)hydroquinone.

11. A photographic element comprising a paper support and a photographicsilver halide emulsion layer and integral with said photographic elementa water-permeable hydrophilic colloid layer containing a compoundrepresented by the following general formula:

wherein X and Y represent a member selected from the class consisting ofa hydrogen atom, alkyl groups having about 1 to 20 carbon atoms, OH,amine, an aryl group, a halogen atom, a heterocyclic group and membersof a carbocyclic ring, Z represents a member selected from the classconsisting of a hydrogen atom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group, a halogen atom and a heterocyc'licgroup and R represents a member selected from the class consisting of anaryl group and a lower alkyl group.

12. A photographic element comprising a flexible support having thereona photographic silver halide emulsion layer and integral with saidphotographic element a waterpermeable hydrophilic colloid layercontaining a compound represented by the following general formula:

having about 1 to 20 carbon atoms, OH, amine, an aryl group, a halogenatom and a beterocyclic group and R represents a member selected fromthe class consisting of an aryl group and a lower alkyl group.

13. .A silver halide photographic developer containing a compoundrepresented by the following general formula:

wherein X and Y represent a member selected from the class consisting ofa hydrogen atom, alkyl groups having about 1 to 20 carbon atoms, OH,amine, an aryl group, a halogen atom, a heterocyclic group and membersof a carbocyelic ring, Z represents a member selected from the classconsisting of a hydro-genatom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group, a halogen atom and a heterocyclic groupand R represents a member selected from the class consisting of an arylgroup and a lower alkyl group.

14. A silver halide photographic developer solution containing .a silverhalide developer and a compound rep resented by the following generalformula:

I N-N NN Y Z wherein X and Y represent a member selected from the classconsisting of a hydrogen atom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group, a halogen atom, a heterocyclic groupand members of a carbocyclic ring, Z represents a member selected fromthe class consisting of a hydrogen atom, alkyl groups having about 1 to20 carbon atoms, OH, amine, an aryl group, a halogen atom and aheterocyclic group and R represents a member selected from the classconsisting of an aryl group and a lower alkyl group.

15. A process for forming a visible photographic image comprisingdeveloping an exposedv photographic element comprising a support and aphotographic silver halide emulsion layer, and integral with saidphotographic element, a water-permeable hydrophilic colloid layercontaining a compound represented by the following general formula:

wherein X and Y represent a member selected from the class consisting ofa hydrogen. atom, alkyl groups having about 1 to 20 carbon atoms, OH,amine, an aryl group, a halogen atom, a heterocyclic group and membersof a carbocyclic ring, Z represents a member selected from the classconsisting of a hydrogen atom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group, a halogen atom and a heterocyclic groupand R represents a member selected from the class consisting of an arylgroup and a lower alkyl group by inbibing throughout said photographicsilver halide emulsion layer an aqueous alkaline solution containingsutllcient alkali to give a pH of at least about 9.0.

16. A process for forming a visible photographic image comprisingdeveloping an exposed photographic element comprising a support havingthereon a photographic silver halide gela-tino emulsion layer containinga silver halide developer and a compound selected from the class ofcompounds represented by the following general formula:

I NN

N N Y wherein X and Y represent a member selected from the classconsisting of a hydrogen atom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group, a halogen atom, a heterocyclic groupand members of a carbocyclic ring, Z represents a member selected fromthe class consisting of a hydrogen atom, alkyl groups having about 1 to20 carbon atoms, OH, amine, an aryl group, a halogen atom and aheterocyclic group and R represents a member selected from the classconsisting of an aryl group and a lower alkyl group, by imbibingthroughout said photographic silver halide emulsion layer an aqueousalkaline solution containing sufiicient alkali to give a pH of at leastabout 9.0.

17. A process for forming a visible photographic image comprisingdeveloping an exposed photographic element comprising a support and aphotographic silver halide emulsion layer, and integral with saidphotographic element, a water-permeable hydrophilic colloid layercontaining a compound selected from the class of compounds representedby the following general formula:

I /N-N X- SC/ N-N Y Z l wherein X and Y represent a member selected fromthe class consisting of a hydrogen atom, alkyl groups having about 1 to20 carbon atoms, OH, amine, an aryl group, a halogen atom, aheterocyclic group and members of a carbocyclic ring, Z represents amember selected from the class consisting of a hydrogen atom, alkylgroups having about 1 to 20 carbon atoms, OH, amine, an aryl group, ahalogen atom and a heterocyclic group and R represents .a memberselected from the class consisting of an aryl group and a lower alkylgroup by imbibing throughout said photographic silver halide emulsionlayer an aqueous alkaline solution containing a silver halide developer.

18. A process for forming a photoresist comprising exposing aphotographic silver halide emulsion layer containing a tanning silverhalide developer and a compound selected from the class of compoundsrepresented by the following general formula:

wherein X and Y represent a member selected from the class consisting ofa hydrogen atom, alkyl groups having about 1 to 20 carbon atoms, OH,amine, an aryl group, a halogen atom, a heterocyclic group and membersof a carbocyclic ring, Z represents a member selected from the classconsisting of a hydrogen atom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group, a halogen atom and a heterocyclic groupand R represents a member selected from the class consisting of an arylgroup and a lower alkyl group, developing in an alkaline bath, andremoving the untanned areas in warm Water.

19. A process for forming a visible photographic image comprisingdeveloping an exposed photographic element comprising a support and aphotographic silver halide emulsion layer by imbibing throughout saidemulsion a silver halide developer solution containing a compoundselected from the class of compounds represented by the followinggeneral formula:

wherein X and Y represent a member selected from the class consisting ofa hydrogen atom, alkyl groups having about 1 to 20 carbon atoms, OH,amine, an aryl group, a halogen atom, .a heterocyclic group and membersof a carbocyclic ring, Z represents a member selected from the classconsisting of a hydrogen atom, alkyl groups having about 1 to 20 carbonatoms, OH, amine, an aryl group, a halogen atom and a heterocyclic groupand R represents a member selected from the class consisting of an arylgroup and a lower alkyl group.

References Cited UNITED STATES PATENTS 2,801,171 7/1957 Fierke et a1 9610O 3,017,270 1/1962 Tregillus et a1. 9676 3,043,690 7/1962 Green et a1.9666 3,155,507 11/1964 Blake 9695 2,315,966 4/1943 Knott 9695 2,981,6244/1961 Dersch 96109 2,977,372 3/1961 Finnegan et a1. 260308 3,123,6153/1964 Rorig 260308 3,227,554 1/1966 Barr et al. 96-3 FOREIGN PATENTS812,673 4/ 1959' Great Britain.

NORMAN G. TORCHIN, Primary Examiner.

C. E. DAVIS, A. D. RICCI, Assistant Examiners.

1. A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT AND A PHOTOGRAPHIC SILVERHALIDE EMULSION LAYER, AND INTEGRAL WITH SAID PHOTOGRAPHIC ELEMENT AWATER-PERMEABLE HYDROPHILIC COLLOID LAYER CONTAINING A COMPOUNDREPRESENTED BY THE FOLLOWING GENERAL FORMULA:
 18. A PROCESS FOR FORMINGA PHOTORESIST COMPRISING EXPOSING A PHOTOGRAPHIC SILVER HALIDE EMULSIONLAYER CONTAINING A TANNING SILVER HALIDE DEVELOPER AND A COMPOUNDSELECTED FROM THE CLASS OF COMPOUNDS REPRESENTED BY THE FOLLOWINGGENERAL FORMULA: